code: def testPair(self):
      done = True
      rank = MPI.COMM_WORLD.Get_rank()
      if rank < 2:
          world_group = MPI.COMM_WORLD.Get_group()
          local_group = world_group.Incl([rank])
          remote_group = world_group.Incl([1 - rank])
          world_group.Free()
          try:
              comm = MPI.Intercomm.Create_from_groups(
                  local_group,
                  0,
                  remote_group,
                  0,
              )
              self.assertEqual(comm.Get_size(), 1)
              self.assertEqual(comm.Get_remote_size(), 1)
              comm.Free()
          except NotImplementedError:
              done = False
          finally:
              local_group.Free()
              remote_group.Free()
      done = MPI.COMM_WORLD.allreduce(done, op=MPI.LAND)
      if not done:
          self.assertLess(MPI.VERSION, 4)
          self.skipTest("mpi-intercomm-create_from_groups")
  
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 1 for calling the TestIntercommCreateFromGroups obj's underlying member method code with example usage: obj.testPair() without return types